1. Background of the Invention
The present invention is in the field of building illumination and particularly relates to an improved skylight for collecting sunlight and directing it into the interior of the building for illumination purposes.
2. The Prior Art
It is possible to characterize the prior art inventions broadly as including a collector for receiving and redirecting the sunlight, a tube or duct for conducting the light to the interior of a building, and a diffuser for producing a more uniform distribution of light within the building. Patentability appears to result from novel designs for each of the elements, and combinations thereof. U.S. Pat. No. 1,254,520 issued Jan. 22, 1918 to MacDuff is typical of the prior art. MacDuff shows a globular light collector oriented vertically and mounted on the roof of a building. The inner surface of the globular light collector includes prismatic elements, and the light is said to be collimated by a circular concave reflector, a convex circular mirror, and rectifying lenses. The collimated light is directed through the ducts in which plane mirrors are used to reflect the light where the direction of the duct changes. A diffusing lens and a fixture are used to spread the beam into many directions within the room to be illuminated.
A similar system is shown in U.S. Pat. No. 3,551,559 issued May 12, 1970 to Foster. The collector used by Foster is oriented vertically and produces a collimated beam of light, but the design of the collector is quite different from that used by MacDuff. Foster also uses plane mirrors in a duct to direct the collimated light to a diffuser. The diffuser used by Foster is different from that used by MacDuff, and it directs the light toward the ceiling of the room to be illuminated to provide an indirect lighting.
In U.S. Pat. No. 668,404 issued Feb. 19, 1901, Hanneborg shows a conical reflector oriented vertically into which direct sunlight is reflected by a large plane mirror that can be manipulated by an operator located in the interior of the building. Hanneborg makes no attempt to collimate the light, which is passed by multiple reflections through a tube to a diffuser.
A fuller discussion of these and other patents is included in the Prior Art Statement filed concurrently with the present application and included within the present file. As will presently be seen, the present invention is simpler than the inventions known in the prior art and at the same time is more efficient.